Shop Windows to the Universe

This ultraviolet image of the Sun shows one of the largest solar flares ever seen. The flare, which erupted in November 2003, is the bright region along the Sun's right limb. The horizontal "spikes" extending to the right and left of the flare are not real; they are an artifact produced by the imaging instrument, which was overloaded by the intense brightness of this flare.
Click on image for full size Image courtesy SOHO (NASA & ESA).

Although solar flares can be visible in white light, they are often more readily
noticed via their bright X-ray and ultraviolet emissions. Coronal
mass ejections often accompany solar flares, though scientists are still trying to determine
exactly how the two phenomena are related. Solar flares burst forth from the
intense magnetic fields in the vicinity of active
regions on the Sun. Solar
flares are most common during times of peak solar
activity, the "solar max"
years of the sunspot cycle.

Shop Windows to the Universe Science Store!

Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store.

You might also be interested in:

The Sun has a very large and very complex magnetic field. The magnetic field at an average place on the Sun is around 1 Gauss, about twice as strong as the average field on the surface of Earth (around...more

Electromagnetic radiation is the result of oscillating electric and magnetic fields. The wave of energy generated by such vibrations moves through space at the speed of light. And well it should... for...more

Radio waves are a type of electromagnetic radiation. A radio wave has a much longer wavelength than does visible light. We use radio waves extensively for communications. Radio waves have wavelengths as...more

An active region on the Sun is an area with an especially strong magnetic field. Sunspots frequently form in active regions. Active regions appear bright in X-ray and ultraviolet images. Solar activity,...more

Sunspots are dark, planet-sized regions that appear on the "surface" of the Sun. Sunspots are "dark" because they are colder than the areas around them. A large sunspot might have a temperature of about...more

Interested in doing a project related to space weather for a science fair? The Stanford SOLAR Center provides information about space weather monitors that you can build yourself, including the Sudden...more

Sunspots are caused by very strong magnetic fields on the Sun. The best way to think about the very complicated process of sunspot formation is to think of magnetic "ropes" breaking through the visible...more